1. Field of the Invention
The present invention relates to optimization of a multichannel sound system, and more particularly, to optimization of the performance of a multichannel sound system based upon input signals and multichannel response data.
2. Related Art
Typically, factory-installed vehicle sound systems are not amenable to aftermarket upgrades. Typically the sound systems have audio and video integrated components that are specifically designed with housings to fit specific models of a vehicle. The signal processing of these sound systems are also typically closed systems that make the modifying or reprogramming of them impractical or impossible.
The signal processing in these types of sound systems is implemented for appropriate or predetermined sound system performance, which often includes crossover and equalization filters that may be contained or tightly integrated in a head unit or an amplifier of an existing sound system that typically cannot be replaced or modified. Only final loudspeaker feeds for tweeters, midrange speakers and woofers are commonly accessible for sound system owners who desire to upgrade their sound systems with external aftermarket audio equipment. The filters implemented in the factory signal processor are normally not user-adjustable, so no method of changing or improving their performance or making adjustments appropriate for new speakers or amplifiers is available.
Prior attempts to partially solve this problem have been put forth, such as an approach to automatically generate gain coefficients for a graphic equalizer. This approach is not desirable because it requires manual user interaction that involves trial and error, i.e. finding and summing up channels with sufficient audio bandwidth, dynamic range and appropriate output signal topology, without introducing excessive stereo crosstalk. In addition, it is common that available outputs of head units or factory-installed amplifiers or signal processors are delayed differently. Also, a simple sum as used in this approach creates frequency nulls that cannot be equalized.
Accordingly, there is a need for optimizing the performance of a sound system when only inputs and outputs of the audio system are accessible. In particular, it is desirable to compensate for crosstalk, band limitations, and sample rate deviations when optimizing performance of the audio system when the crossover and equalization filters of existing sound system or head unit are unknown.